It was forever ago, that afternoon when a family member observed Damon Huard’s tangled-up pregame psyche and said, “Right now, he’s one nervous little guy.”

It was 17 days ago.

That’s the beauty of having an open date. For Kansas City, it turned Huard from game manager to gunslinger, sullen to strutting. Huard was clutching onto his Nike sunglasses late Sunday, because the glare was that bright and the backup quarterback was that big in the Chiefs’ 41-0 win over San Francisco.

He laughed when reminded that nobody, outside of maybe the Chiefs’ locker room, thought he could carry a game with his arm the way he did Sunday.

“That’s OK,” he said. “I haven’t played much.

“If you stay at the table long enough, you’re going to be dealt some cards.”

Everything, from the clear skies that replaced the pelting rain to the appearance on the sideline of Trent Green, was different from the last time Kansas City played at Arrowhead Stadium on Sept. 10. The same Chiefs offense dubbed conservative and inept scored on its first two possessions and piled up 24 points by halftime.

The same backup quarterback who stumbled through that game against the Bengals was poised and as cocky as Damon Huard can be. In one of the biggest displays of emotion by a Chiefs quarterback in recent memory, Huard hit Dante Hall with a 13-yard touchdown pass on the opening drive and then stood on the 42, arms in the air and head to the sky, and pumped his fist three times before bouncing off the field.

He slammed his Gatorade cup into the trash bin. It had been a long two weeks in Kansas City, and the words “must win” filled meeting rooms and practice fields. Coach Herm Edwards, who says he never panics, made it clear that an 0-3 start would at least be time to squirm.

“They had no excuse for not winning this game,” Edwards said. “They had to win, period. We were going to play all day until we won the football game.”

Everyone, from the kicker to the defense to Edwards, knew the sense of finality another home loss would bring. For three weeks, Edwards was answering questions about why his offense was so conservative and whether his defense was finally fixed. The latter question may have been answered by the fourth quarter, when the Chiefs were finishing their first shutout in four years.

Kansas City forced four turnovers, racked up 23 first downs and smothered the NFL’s fifth-ranked offense.

“That’s a big game, you know?” right tackle Kevin Sampson said. “It was a must win. There were no other options for us.”

The day started with roughly 77,000 erupting in applause when Green’s face flashed on the big screens. Green was on the sideline for the first time since being knocked unconscious in the Bengals game, and the Chiefs said later that he had a calming influence on the team.

The vibes permeated through Huard. He marched the Chiefs 60 yards at the start of the game and then threw a perfect pass to Hall in the corner of the end zone. It was just the second touchdown of the season for an offense that ranked as the NFL’s best in 2005. It was just the start for Huard.

Edwards said he could see it in his quarterback’s eyes, the confidence. Two weeks ago, Huard was thrust into his first start in six years at Denver. He didn’t get the win but kept the Chiefs in the game in a 9-6 overtime loss. And Sunday, after two weeks of developing a rhythm and some chemistry with his receivers, Huard was ready.

He hit 13 of his first 15 passes and had 152 yards and two touchdowns by halftime. He put the 49ers on their heels when they tried to stack against the run.

“He was like a little kid out there,” tight end Jason Dunn said. “I’ll tell you what, he benefited from that week off. You’ve got to go back to the basics of having fun. You’ve got to go back to being 11 years old again.”

Or 33 and rejuvenated. Chiefs guard Brian Waters found Huard’s first-quarter touchdown celebration endearing, mainly because it had seemed like forever since they’d scored a touchdown. Actually, it had been three weeks before Sunday.

And in Kansas City, that’s an eternity.

“I guess I was a little animated and excited because that first touchdown, that first drive, just felt good,” Huard said. “Guys made plays, and boy, it was fun.”